Device and process for marking an ophthalmic lens with a pulsed laser of wavelength and energy selected per pulse

Patent metadata

Field	Value
Publication number	US-2016207249-A1
Application number	US-201414917113-A
Country	US
Kind code	A1
Filing date	Sep 19, 2014
Priority date	Sep 20, 2013
Publication date	Jul 21, 2016
Grant date	—

Abstract

A device for marking an ophthalmic lens ( 3 ), the lens ( 3 ) being made of at least one preset material, includes a laser ( 1 ) configured to produce permanent engravings on the lens ( 3 ) and configured to emit a focused beam of pulsed ultraviolet laser radiation that includes at least one radiation wavelength ranging between 200 nm and 300 nm, has a pulse length ranging between about 0.1 ns and about 5 ns, and has an energy per pulse ranging between about 5 μJ and about 100 μJ. A laser marking process configured to produce permanent engravings on an ophthalmic lens ( 3 ) via this device is also described.

First claim

1 . A device for marking an ophthalmic lens, said ophthalmic lens being produced from at least one predetermined material, including a laser configured to produce permanent engravings on the ophthalmic lens, wherein the laser is configured to emit a focused pulsed beam of ultraviolet laser radiation, the focused beam having at least the following parameters:
a radiation wavelength comprised between 200 nm and 300 nm; a pulse duration comprised between about 0.1 ns and about 5 ns; and an energy per pulse comprised between about 5 μJ and about 100 μJ.

2 . The device as claimed in claim 1 , wherein the focused beam furthermore has at least one of the following parameters:
a peak power comprised between about 2.5 kW and about 1 MW; and/or a pulse frequency comprised between about 100 Hz and about 10 kHz.

3 . The device as claimed in claim 1 , wherein the radiation wavelength of the focused ultraviolet laser beam is comprised between about 230 nm and about 290 nm and preferably about 266 nm.

4 . The device as claimed in claim 1 , further including a solid-state laser source configured to emit a pulsed infrared radiation beam, and a multiplier, positioned at the output of the laser source and configured to multiply a radiation frequency of the infrared beam emitted as output from the laser source, preferably by a factor comprised between three and ten.

5 . The device as claimed in claim 4 , wherein the laser source is an Nd-YAG laser and in that the multiplier is configured to quadruple the frequency of pulses output from the Nd-YAG laser.

6 . The device as claimed in claim 4 , wherein the laser source is configured to emit a pulsed beam of laser radiation having an energy per pulse comprised between about 30 μJ and about 80 μJ and preferably higher than 40 μJ.

7 . The device as claimed in claim 1 , further including an optical assembly provided with an F-theta lens, which lens is configured to focus a beam of ultraviolet laser radiation onto a focal plane of the F-theta lens with a focused beam diameter in the focal plane of the order of about 20 μm to about 50 μm.

8 . The device as claimed in claim 7 , wherein the optical assembly includes an energy attenuator configured to regulate a fluence of the beam of ultraviolet radiation focused on a surface of the ophthalmic lens to be marked according to a plurality of operating modes of the attenuator, which modes each define a determined fluence value.

9 . The device as claimed in claim 8 , wherein the operating modes of the attenuator and/or the fluence values determined for said operating modes are defined on the basis of at least one parameter of the material of the ophthalmic lens, which parameter is chosen from a degradation parameter and an absorbance at the wavelength of the ultraviolet radiation.

10 . The device as claimed in claim 8 , wherein the device is configured to be able to calibrate the attenuator by determining a curve representing an energy per pulse of the focused beam, as a function of an angle of orientation of a polarized filter that the attenuator includes, for a given energy per pulse at the input of the attenuator.

11 . The device as claimed in claim 7 , wherein the optical assembly furthermore includes a scanner head configured to pilot an orientation of the beam of ultraviolet laser radiation toward the F-theta lens, and to pilot a position of the focused laser beam in the focal plane of the F-theta lens.

12 . The device as claimed in claim 7 , further including a mechanism for adapting a distance between the optical assembly and a holder of the ophthalmic lens to be marked, which adapting mechanism is configured to modify an altitude of the ophthalmic lens to be marked.

13 . The device as claimed in claim 1 , wherein at least one of the engravings defines a marking formed by a plurality of spots produced at a distance from one another with a predetermined separation between two consecutive spots.

14 . The device as claimed in claim 1 , wherein at least one of the engravings defines a technical marking on a surface of the ophthalmic lens, which ophthalmic lens has a predetermined prescription.

15 . The device as claimed in claim 1 , wherein at least one of the engravings defines a commercial marking on a surface of the ophthalmic lens, which ophthalmic lens has a predetermined prescription and optionally a functional treatment.

16 . A process for marking an ophthalmic lens produced from at least one predetermined material, the process being implemented by a device as claimed in claim 1 , and the process including a step of laser marking permanent engravings on the lens, which marking step includes a step of emitting a focused pulsed beam of ultraviolet laser radiation having at least the following parameters:
a radiation wavelength comprised between 200 nm and 300 nm; a pulse duration comprised between about 0.1 ns and about 5 ns; and an energy per pulse comprised between about 5 μJ and about 100 μJ.

17 . The process as claimed in claim 16 , wherein the at least one engraving is produced on a surface of the ophthalmic lens, which ophthalmic lens has a predetermined prescription and said surface is devoid of functional treatment.

18 . The process as claimed in claim 16 , wherein the at least one engraving is produced on a surface of the ophthalmic lens, which ophthalmic lens has a predetermined prescription and is provided with at least one functional treatment.

19 . The device as claimed in claim 2 , further including a solid-state laser source configured to emit a pulsed infrared radiation beam, and a multiplier, positioned at the output of the laser source and configured to multiply a radiation frequency of the infrared beam emitted as output from the laser source, preferably by a factor comprised between three and ten.

20 . The device as claimed in claim 9 , wherein the device is configured to be able to calibrate the attenuator by determining a curve representing an energy per pulse of the focused beam, as a function of an angle of orientation of a polarized filter that the attenuator includes, for a given energy per pulse at the input of the attenuator.

Assignees

• Essilor Int

Inventors

• Maurice Sebastien
• Dubois Frederic

Classifications

• B23K2103/50

  Inorganic materials other than metals or composite materials · CPC title

• B23K26/0006 Primary

  taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence) · CPC title

• B23K26/361

  for deburring or mechanical trimming (B23K26/351 takes precedence) · CPC title

• B23K26/0648

  comprising lenses · CPC title

• B29C59/16 Primary

  by wave energy or particle radiation {, e.g. infrared heating (B29C59/007 takes precedence)} · CPC title